<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>

    ul,li{
      list-style: none;
      margin: 0;
      padding: 0;
    }
    .container{
      display: flex;
      width: 500px;
      height: 500px;
      background: orange;
    }
    .container .item{
      width: 120px;
    }
    .item1{
      background-color: antiquewhite;
    }
    .item2{
      background-color:aqua;
    }
    .item3{
      background-color:aquamarine;
    }
  </style>
</head>
<body>
  <ul class="container">
    <li class="item item1"></>
    <li class="item item2"></>
    <li class="item item3"></>
  </ul>
</body>
</html>